Flashback: It’s first grade at Webster Elementary School in Manchester, N.H., and Adam Sandler, 6, suddenly asks the teacher to be excused. He runs out the door, up the hill to Madeline Road, and home to his mother. She gives him a peanut butter and jelly sandwich, and tells him that when he’s finished he has to go back to school. So he sits and eats, and she escorts him back down the hill. End of drill.

Fast-forward: It’s early morning on the set of Universal’s feature comedy Billy Madison, and Adam Sandler, now 28, is having difficulty dealing with his alarm clock. He’s lying on a massive bed, surrounded by boy toys (a basketball hoop, air hockey game, hanging bicycles, etc.). He’s sporting a pair of flannel pajamas, adjusting his crotch (”I’m trying not to make it look too fat, so it won’t intimidate people”), and joking with anyone within earshot. The star and cowriter of Madison, Sandler plays a spoiled goof-off who’s attempting to prove his mettle and secure his inheritance by repeating grades 1 through 12 and making it to graduation. Twenty-two years later, Adam Sandler is still trying to get the school thing down.

Pajamas or no, Sandler looks like he’s goofing off even when he’s intensely focused. He’s that funny guy we all knew in high school who was smart enough to make it look easy, and charmed his way through — only he’s turned pro with it. ”Sometimes you don’t think he’s working; he’s just doing what Adam is,” says his mother, Judy.

So far, Sandler’s high school shtick has served him well. He’s in his fourth season as a Saturday Night Live performer (and fifth as a writer), specializing in moronic characters (Opera Man, Canteen Boy), silly holiday tunes (”Put on your yarmulke, Here comes Hanukkah”), and endearing losers. He’s also had some secondary movie roles (Coneheads, Airheads) and his 1993 gold-selling comedy album, they’re all gonna laugh at you!, recently snagged a Grammy nomination. But Sandler’s graduation to adulthood is looming. His recent minor role in Nora Ephron’s Christmas debacle Mixed Nuts garnered some harsh reviews. SNL seems to be cooling off. And this month, he puts himself to the manly test of carrying a film.

”I know it’s gonna hurt if [the movie] eats it,” Sandler says. ”Billy’s the closest I’ve come to playing myself. I feel so much pressure because I want it to be as good as it can be.” But he also appreciates his current position. ”Dennis Miller told me that you only get famous once and then you are famous. But the best part is becoming famous. Right now I’m the underdog. It feels good.”

Sandler is smarter than he likes to let on, but he prefers playing idiotic characters because he thinks losers are more interesting. He can’t stand being alone. He can’t believe that he can get away with saying the F-word in front of his father, Stan, a retired electrical engineer. His long-distance bill is about $700 a month; if no one’s around he’ll call the Domino’s guy to chat. His phone conversations never begin with ”Hello.” He’ll sing, imitate a woman’s voice (often his grandmother’s), or play some kind of joke. Occasionally he wakes up his fiancée, cosmetics-company manager Margaret Ruden, 28, to keep him company in the wee hours. ”The only thing that makes me think I’m not crazy is that I know I’m crazy,” he says.

Because he likes company for his craziness at all times, Sandler usually involves his comedy buddies in his work. Fellow SNL alum Rob Schneider and Madison cowriter Tim Herlihy, a good friend of Sandler’s since they roomed (and memorized Caddyshack) together freshman year at New York University, helped him write the album. SNL friends David Spade, Tim Meadows, and Conan O’Brien performed on it. Other SNL buddies Chris Farley, Norm MacDonald, and former writer Robert Smigel have parts in Madison. Sandler initially picked Stephen Kessler, who gave him his first break in a commercial, to direct. Two weeks into shooting, Universal decided to replace Kessler. ”The studio wanted a less stylized movie, more of me being a goof,” says Sandler. ”It was very sad, like breaking up with a girlfriend. But he’s doing well.”

In the SNL office he shares with Spade, Sandler alternates between strumming his Gibson guitar and doing voices. The room looks like it’s been through a washing machine’s spin cycle: piles of fan mail, a sombrero, trash, a New Kids on the Block calendar, a prom invitation from some high school girls in Trumbull, Conn. ”He’s goofy, but the girls like him,” says MacDonald. ”He’s Lewis and Martin rolled into one.”

Serious Man, he’s not. When he plays a sensitive song he’s written, he can’t look up. Same thing when Chris Farley stops in and they do a soulful ”Beast of Burden.” ”When we’re alone we can be sensitive,” Sandler says of this less- than-macho moment. ”But when other people are around we start talking about dildos and stuff to let ’em know we’re still funny.”

About the only thing Sandler is serious about is his comedy. Madison replacement director Tamra Davis (CB4, Guncrazy) is quick to attest to his dedication. ”He’d call me every night after dailies, and we’d talk about the movie for an hour.” Herlihy, too, testifies to his friend’s perfectionist nature: ”We’d argue for hours about whether someone says ‘Come on in’ or ‘Come on in and have a seat.”’ Universal, however, has no complaints with the team. The studio recently signed a deal for Happy Gilmore, another Sandler-starring script about a ”blue-collar moron” on the PGA tour. It’s a good thing comedy continues to keep Sandler employed. According to Herlihy, he’s never been able to hold down a conventional job for more than two weeks.